1. Field of the Invention
The present invention relates to towing devices used to tow airplanes. More particularly, the present invention relates to a towing adapter to maintain the struts of an airplane at a desired configuration during towing.
2. Background of the Related Art
Airplanes often have to move around an airport by tow vehicles, such as to between gates or to pull into or out of a gate. FIG. 1 shows a front wheel assembly of an airplane fitted with a torque link assembly 10. The torque link assembly 10 can include two struts 12, 14 that connect to the wheel assembly about the wheel 16 and axle 18. The torque link assembly 10 is shown in a storage position for operation of the airplane without towing. The struts 12, 14 are elongated metal arms that are connected to one another about a central pivot point 20. The lower strut arm 14 is connected to a lower portion of the vertical plane axle at a lower connection point 22. The upper strut arm 12 is connected to an upper portion of the vertical plane axle at an upper connection point 24. The lower connection 22 permanently connects the torque link assembly 10. The lower strut 14 can rotate up and down about the lower connection 22.
In the storage position, the struts 12, 14 are folded up and the top strut 12 is connected to the vertical axle of the wheel assembly at the upper connection point 24. The torque assembly 10 is thereby locked to the aircraft and does not move. The torque assembly 10 is moved to the operating position when the airplane needs to be towed. Here, the top strut 12 is released from the upper connection point 24 and lowered downward. The central pivot point 20 allows the strut arms 12, 14 to rotate with respect to one another, so that the arms 12, 14 can be lowered down and properly positioned for attachment to a tow vehicle. The torque assembly 10 can only move in the up and down directions. The torque assembly 10 itself does not move in the left and right direction, but instead moves the plane wheel assembly left and right for towing and positioning.
One difficulty with the torque assembly 10 is that the lower connection 22 and/or the pivot connection 20 can over-rotate. And, the torque links are unsupported and unrestrained. Consequently, the strut arms 12, 14 can lower all the way down until the upper strut arm 12 hits the ground, an object, or the aircraft, potentially causing injury or damage.